Cartilage / Meniscus Tear

There are two meniscus in the knee known as meniscii, lateral and medial. The menisus are roughly c-shaped and made up of a very tough fibrocartilage. They are positioned between the Tibia (shin bone) and femur (thigh bone) on the outer aspect of the joint.

The meniscus perform the following important functions in the knees:

Improve load transmission – Due to there shape they are able to increase to contact area between the tibia and femur so forces can be transmitted over a larger area, some research as shown that as much as half of the contact area is lost when a complete meniscetomy is performed, a procedure which involves the removal of the whole meniscus.

Increase stability of the knee joint - the femoral condyles (end of the thigh bone) and the tibial plateux (end of the shin bone) are not a perfect fit. The meniscus shape helps form a deeper socket for the Femoral condyles to fit into. They assist in both guiding and limiting the flexion (bending) and extending (straightening) of the joint.

Improve shock absorption: The cartilage has a high water content and acts as a sponge dampening compressive loads on the joint.

Lubrication- The loading and unloading of the meniscus helps the movement of fluid around the inside of the joint this fluid contains essential nutrients to maintain joint health.

Proprioception (joint position sense): the meniscus has small nerve sensors which work on a feedback type mechanism to help protect the joint from any dangerous positions

The most common mechanism for damaging the menisci is a compressive and twisting action with the knee flexed (bent) with the foot planted. This mechanism is not dissimilar to the ACL rupture and they may frequently occur at the same time.

Symptoms

When a patient experiences an acute meniscus tear they often describe pain, joint swelling this may be rapid or slow depending on the severity of the injury, locking/catching of the knee joint (in sever cases), giving way, tenderness (if medial meniscus this may inside part of knee), limited movement of the knee. There is often a mix of symptoms and if the damage is more chronic in nature such as arthritis and wear and tear the symptoms can be quite mild.

Meniscus tears can often be diagnosed by MRI scan although in some cases they are only picked up through Arthroscopy (a key hole procedure using a camera to look inside the joint).

 treatment

The meniscus doesn’t have a good blood supply with only the outer portion of the medial meniscus having blood vessels. This means at it’s not very quick to heal when damaged and may not heal at all. Patients are generally advised to rest and avoid any activities which involve twisting and compressing the joint such as jumping and kicking.   If the damage is severe or conservative care measures have failed then a orthopaedic consultant opinion should be sort with a view to partial meniscetomy  (shaving off the damaged cartilage via key hole surgery) or a meniscus repair.

if you have any questions regarding this injury, please do not hesitate to contact us at enquiries@body-motion.co.uk